WASHINGTON — Attorney General Michael Mukasey refused Friday to give Congress details of the government's investigation into interrogations of terror suspects that were videotaped and destroyed by the CIA. He said doing so could raise questions about whether the inquiry is vulnerable to political pressures.

In letters to leaders of the House and Senate Judiciary committees that oversee the Justice Department, Mukasey said there is no need right now to appoint a special prosecutor to lead the investigation. The preliminary inquiry is being handled by the Justice Department and the CIA's inspector general.

"I am aware of no facts at present to suggest that department attorneys cannot conduct this inquiry in an impartial manner," Mukasey wrote Friday to Sens. Patrick Leahy of Vermont and Arlen Specter of Pennsylvania, the top Democrat and Republican, respectively, on the Senate Judiciary Committee. "If I become aware of information that leads me to a different conclusion, I will act on it."

Meantime, Senate Republicans blocked a bill Friday that would restrict the CIA's interrogation methods. Already passed by the House, the bill would require the CIA to adhere to the Army's field manual on interrogation, which bans waterboarding, mock executions and other harsh methods.

Senate opponents discovered a parliamentary flaw: The ban on harsh tactics had not been in the original intelligence bills passed by the House and Senate. Instead, it was added during negotiations between the two chambers to write a compromise bill. That move could violate a Senate rule intended to protect legislation from last-minute amendments that neither house of Congress has had time to fully consider.

Although it's not unheard of for new language to be added in House-Senate negotiations, the rules allow such a move to be challenged and the language stripped from the bill. Sen. Lindsay Graham, R-S.C., placed a hold on the bill while the GOP procedural challenge goes forward.

Mukasey's letter draws bipartisan anger
Addressing congressional demands for facts in the CIA tapes inquiry, Mukasey noted that the Justice Department generally does not give out information about pending cases.

"This policy is based in part on our interest in avoiding any perception that our law enforcement decisions are subject to political influence," Mukasey wrote. "Accordingly, I will not at this time provide further information in response to your letter, but appreciate the committee's interests in this matter."

An almost-identical letter was sent Thursday to Democratic leaders of the House Judiciary Committee.

Democratic and Republican lawmakers alike angrily denounced Mukasey's refusal, which they said blocks congressional oversight of the Justice Department.

Additionally, lawmakers from both parties accused the Justice Department of obstructing a House Intelligence Committee inquiry by advising the CIA against cooperating.

"Earlier today, our staff was notified that the Department of Justice has advised CIA not cooperate with our investigation," House Intelligence Chairman Silvestre Reyes, D-Texas, and the panel's top Republican, Rep. Pete Hoekstra of Michigan, said in a joint statement Friday.

"We are stunned that the Justice Department would move to block our investigation," Reyes and Hoekstra said. "Parallel investigations occur all of the time, and there is no basis upon which the Attorney General can stand in the way of our work. ... It's clear that there's more to this story than we have been told, and it is unfortunate that we are being prevented from learning the facts. The executive branch can't be trusted to oversee itself."

Request for delay of inquiry
Assistant Attorney General Kenneth Wainstein and CIA Inspector General John Helgerson, who are heading a joint Justice-CIA preliminary inquiry into the videotape destruction, asked Reyes and Hoekstra by letter on Friday to postpone the Intelligence Committee investigation until it's clear where the preliminary inquiry will lead. They said they could not predict how long that would take.

Wainstein and Helgerson said their inquiry would need the same documents and witnesses the committee has requested. "Our ability to obtain the most reliable and complete information would likely be jeopardized if the CIA undertakes the steps necessary to respond to your requests in a comprehensive fashion at this time," they wrote. They cited particularly the committee's request to interview CIA inspector general personnel "because they are potential witnesses in the matter under our inquiry."

In a letter Thursday to CIA Director Michael Hayden, the House panel had asked the CIA to hand over by Friday all documents and cables regarding the interrogation tapes and their destruction. Based on the Bush administration's response Friday, it appeared likely the administration also would block testimony by acting CIA General Counsel John Rizzo and Jose Rodriguez, the former head of the National Clandestine Service. Both have been summoned to testify to the committee on Dec. 18. Rodriguez ordered the tapes destroyed.

Leahy said he was disappointed that Mukasey denied the details to his committee — even in a classified setting.

Tapes will top intelligence panel agenda
Leahy said the tapes would be a top topic at his committee's hearing next week to consider the nomination of U.S. District Judge Mark Filip for deputy attorney general, the Justice Department's No. 2 official. It also will come up at oversight hearings of the Justice Department that Leahy said he would schedule for early next year.

The videotapes, made in 2002, showed the CIA's interrogations of two terror suspects. They were made to document how CIA officers used new, harsh questioning techniques approved by the White House to force recalcitrant prisoners to talk. The CIA destroyed the tapes in 2005 but acknowledged doing so only last week.

The disclosure brought immediate condemnation from Capitol Hill and from a human rights group which charged the spy agency's action amounted to criminal destruction of evidence.

Intelligence officials have said the methods that were shown on the videotapes included waterboarding, an interrogation tactic that causes the sensation of drowning and is banned by the Pentagon. The issue of waterboarding threatened to derail Senate approval of Mukasey last month.

During his confirmation hearings in October, Mukasey promised senators he would review Justice Department memos after becoming attorney general to determine whether waterboarding amounts to torture — which would deem it illegal. Earlier this week, however, Mukasey said he has not yet finished that review, and rebuffed calls from Congress to make a speedy decision.

Copyright 2007 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.